Interpretive Summary: Southern highbush blueberries (SHB) are mostly hand harvested for the fresh market. Hand harvesting of blueberry is labor intensive (approximately 500 hours/acre) and costly. With the uncertainty of labor availability in the near future, there is need to develop blueberry varieties that develop less bruising after impact with hard surfaces on the harvesters and improve harvest efficiency by horticultural and engineering means. In this study, the fruit of SHBs were either hand- or machine-harvested and assessed during postharvest storage for bruise damage and softening. Studies showed that ground-loss that occurs during machine-harvesting can be reduced by constricting the crown. Fruit drop tests from a height of 40 inches on a plastic surface showed that soft-textured, conventional-flesh blueberries were more susceptible to bruising than the crispy-flesh blueberries. When the contact surface was cushioned with a foam sheet, bruise incidence was significantly reduced in all blueberries. Also, the fruit dropped 40 inches developed more bruise damage than those dropped 20 inches. Machine harvesting contributed to bruise damage in the fruit and softening in storage. Fruit firmness in crispy SHB was higher than in soft-textured SHB. This study addressed problems related to in-field ground loss and postharvest quality of hand- and machine-harvested SHB blueberries. The study demonstrated that mechanical harvest of some crispy SHB blueberries for fresh market is feasible. Additional research is necessary to determine how blueberry quality can be affected by physical damage incurred at harvest.

Technical Abstract:
Southern highbush blueberries (SHB) (Vaccinium darrowi x V. corymbosum) are mostly hand harvested for the fresh market. Hand harvesting of blueberry is labor intensive (approximately 500 hours/acre) and costly. With the uncertainty of labor availability in the near future, efforts are underway to develop blueberry genotypes that will develop less bruising after impact with hard surfaces on the harvesters and improve harvest efficiency by horticultural and engineering means. In this study, the fruit of SHBs were either hand- or machine-harvested and assessed during postharvest storage for bruise damage and softening. Studies showed that ground-loss that occurs during machine-harvesting can be reduced by constricting the crown. Fruit drop tests from a height of 40 inches on a plastic surface showed that soft-textured, conventional-flesh genotypes were more susceptible to bruising than the crispy-flesh genotypes. When the contact surface was cushioned with a Poron foam sheet, bruise incidence was significantly reduced in all genotypes. Also, the fruit dropped 40 inches developed more bruise damage than those dropped 20 inches. Machine harvesting contributed to bruise damage in the fruit and softening in storage. Fruit firmness in crispy-type SHB was higher than in soft-textured SHB. This study addressed problems related to in-field ground loss and postharvest quality of hand- and machine-harvested SHB blueberries. The study demonstrated that mechanical harvest of some crispy SHB blueberries for fresh market is feasible. Additional research is necessary to determine how blueberry quality can be affected by physical damage incurred at harvest.